Ukrainian opposition leaders issued President Viktor Yanukovich with an ultimatum on Wednesday, threatening to launch an offensive if he does not dismiss the government, call early elections, and repeal legislation limiting acts of protest.

The demand came after three of the opposition’s main leaders met with the president for direct negotiations on Wednesday, following the deaths of at least three demonstrators during clashes with police in the capital Kiev.

Two of the victims died of gunshot wounds, while the third is believed to have plunged to his death from the top of the city’s Dynamo football stadium, which was adjacent to the protests.

The deaths were the first protest-related fatalities since the protests first erupted last November after Yanukovich backed out of a landmark treaty with the European Union.

Emerging from the failed talks, boxer-turned-politician Vitaly Klitschko told the thousands of protesters gathered in Kiev’s Independence Square said that he was ready to face police bullets.

“Today they are preparing to clear us out of the ‘Maidan’ (Independence Square),” Klitschko declared, urging protesters to camp out overnight to defend the square. “We must do all we can to stop them clearing us out.”

‘We will go on the offensive’

“Tomorrow if the President does not respond … then we will go on the offensive,” he said, drawing a roar of support from the crowd.

Former economy minister Arseny Yatsenyuk echoed his words, invoking the deaths of the three protesters, which he blamed on the police.

“I will not live in shame. Tomorrow we will go forward together. If there will be a bullet in the forehead, so be it. It will be honest, just and brave action,” he said.

On Thursday, however, Klitschko urged protesters to refrain from confronting the police until at least 6pm (GMT).

The direct talks between Yanukovich and the opposition were the first concrete move towards negotiating an end to two months of civil discontent which have culminated in violent clashes between demonstrators and police over the past few days.

The fighting continued on Wednesday as protesters tried to hold their ground against the police. Fifty people were detained overnight, 29 of whom were officially charged with taking part in mass unrest, police said. A total of 167 police officers were injured, officials said. There was no figure for the number of civilians injured.

‘Against bloodshed’

Ahead of the talks with Klitschko, Yatsenyuk and far-right nationalist Oleh Tyahnibok, Yanukovich issued a statement deploring the deaths.

Urging people not to heed the calls of “political radicals”, Yanukovich said, “I am against bloodshed, against the use of force, against inciting enmity and violence.”

But his prime minister, Mykola Azarov, took a tough public line before flying off to the economic forum in Davos, denouncing the protesters as “terrorists” and “criminals”. He blamed opposition leaders for inciting “criminal action” by backing the protests, which he said had destabilised Ukraine, a country of 46 million people.

The Kiev demonstrations took a violent turn on Sunday after the government passed legislation limiting acts of protest which the opposition says paves the way for a police state in the former Soviet republic.